Servos too loud Philips CD-60

My Philips CD-60 makes an irritating whistle noise which gradually gets louder as the tracks advance toward the middle of the disc, then begins to reduce in volume. Sort of a bell curve. The frequency is about 620 Hz (I matched it on the piano to the 2nd Eb above middle C). At its loudest the noise is audible over the program being played.
I was told by a wise forum member that the noise is caused by the focus and radial servos.
I have to believe it's much louder than is typical. Is there an adjustment that can be made? If not, can someone give me some pointers on deadening? I'm going to try putting Blu-Tack on the underside of the clamp, but I don't think that will be sufficient.